The most interesting and controversial research in exercise science over the past decade or so has focused on the role of the brain in sports performance. How, exactly, do we decide how fast we can go, when to keep pushing and when to give up? Lots of studies have shown how the brain can be tricked -- with drugs, or illusions, or false feedback. But the next stage is just getting underway: peering inside the brain to figure out how it all works. This endeavor is just in its infancy, but interesting studies are starting to emerge, like this one just published in the British Journal of Sports Medicine by a Brazilian group.

They recruited 10 national-class cyclists, applied a direct current to a specific region of their brains for 20 minutes, and then put them through an incremental cycle test to exhaustion. The region they targeted is the left temporal cortex (though the excitation also likely affected the left insular cortex located just below the temporal cortex):

The main result was that peak power output in the incremental test increased by 4% after the brain stimulation. (All 10 riders did the test twice on separate days, under randomized crossover double-blinded conditions, either with the electrical stimulation or with a sham stimulation that was indistinguishable to the subjects.) The data show that early in the tests, the riders already had lower heart rates and lower ratings of perceived exertion after the brain stimulation. (There's also some data showing delayed "parasympathetic vagal withdrawal"; that interpretation is a bit more complex, but basically suggests that the nervous system's transition between "baseline" and "fight-or-flight" dominance happened a little later.)

Why is this? Well, the interpretation of these early brain studies is never straightforward. However, the researchers note that the temporal cortex is involved in the control of heart rate and blood pressure, and the left side (which is what they stimulated) is associated with "pleasant feelings as occurs, for example, when subjects either see or make a smile, or listen to happy voices, or hear pleasant music." In contrast, the right side is associated with pain and elevated perceived exertion. As a result, they suggest that the stimulation may have directly decreased perceived exertion at a given effort level, and thus improved performance on the test.

From a spectator's point of view, I think it's not worth getting too bogged down in which neurons are doing exactly what at this point. It's going to take a long time to figure that stuff out. But this is pretty powerful direct evidence of something that pretty much everyone now acknowledges: in most circumstances, we don't collapse from exhaustion because our muscles or heart or lungs have reached their breaking point. Those signals are filtered through the brain, which makes the final decision. What does that change? I'm really not sure, to be honest... but it still seems important to me, somehow.